Derivative Financial Instruments - Schedule of Total Value by Underlying Risk Recognized in Other Comprehensive Income and Reclassified from AOCI to Statement of Operations (Detail) - USD ($) $ in Millions		3 Months Ended				6 Months Ended
		Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018
Derivative Instruments Gain Loss [Line Items]
Amount of gain (loss) recognized in other comprehensive income (loss)		$ (16)	$ (58)	$ (23)	$ (1)
Revenues	[1]	2,137		1,735		$ 4,348	$ 2,343
Cost of operations		1,949		1,486		3,967	1,962
Interest expense, net		(100)		(72)		(192)	(83)
Designated as Hedging Instrument [Member] | Foreign Exchange Hedges [Member]
Derivative Instruments Gain Loss [Line Items]
Amount of gain (loss) recognized in other comprehensive income (loss)		3		(5)		(4)	(5)
Revenues		(4)				(5)
Cost of operations		2				1
Designated as Hedging Instrument [Member] | Interest Rate Hedges [Member]
Derivative Instruments Gain Loss [Line Items]
Amount of gain (loss) recognized in other comprehensive income (loss)		(28)		(10)		(43)	(10)
Interest expense, net		(2)				(3)
Derivatives not Designated as Hedges [Member] | Foreign Exchange Hedges [Member]
Derivative Instruments Gain Loss [Line Items]
Revenues		$ 1				$ 2
Cost of operations				$ (10)			$ (10)

[1] Intercompany amounts have been eliminated in consolidation.